Problem Statement:

rajk00071 [10:20 AM]
can namerctl handle base url with https endpoint
[10:20]
i am getting /api/1/dtabs: x509: certificate signed by unknown authority
[10:20]
although i know my certs are valid

Answer:

olix0r [11:08 AM]
hmm. namerctl may not handle that properly yet. sounds like a good PR though!

Since it was suggested, I just wanted to throw this issue on here so that we could track it in case anyone else was having similar issues, or has solved it already.

It's awkward to reasonable usage/help messaging with subcommands and the native flag library. I think we should try to use cobra do build a proper CLI: https://github.com/spf13/cobra

We check the version of the dtab on namerctl dtab update if we send the dtab in json format (and do a versioned update), but we don't if the dtab is sent via yaml, where the version is included in a comment (i.e. we do a versionless update).

If you just have a json file without setting the version key, (or a yaml file with or without the version included as a comment) then both json and yaml behave the same, i.e. will do versionless updated unless a version is provided using the --version flag.

This is confusing for users (#21). We should standardize. i.e. when a version is included in json or yaml, we should use it in both cases.

Example

When you do a namerctl dtab get <dtab namespace>, namerctl prints the dtab string with the version as a yaml comment. The user can then make updates to the dtab they received and run a namerctl dtab update <dtab namespace> and the update will work:

$ namerctl dtab get default
# version AAAAAAAAAAQ=
/svc  => /#/io.l5d.fs ;

$ namerctl dtab get default > default.yaml

# update default.yaml without changing the version
$ namerctl dtab update default default.yaml
Updated default

# update default.yaml *again* without changing the version
$ namerctl dtab update default default.yaml
Updated default

However, if you do the same steps, but add --json, you'll get a unexpected response: 412 Precondition Failed because we do check the version if it's included in the json payload:

$ namerctl dtab get default --json
{"version":"AAAAAAAAAAg=","dtab":[{"prefix":"/svc","dst":"/#/io.l5d.fs"}]}

$ namerctl dtab get default --json > default.json

# update default.json without changing the version
$ namerctl dtab update default default.json
Updated default

# update default.json *again* without changing the version
$ namerctl dtab update default default.json
Error: unexpected response: 412 Precondition Failed

By mistake I've used admin port (9991) instead of http (4181).
And run command: namerctl dtab create incoming incoming --base-url "http://host:9991"
After that I got message: Created incoming and didn't have an error

When I run: namerctl dtab ls --base-url "http://host:9991"
I got: Error: invalid character '<' looking for beginning of value

Intro

1. when you update a dtab it gets assigned with a new version value.
2. namerctl doesn't check the version value included in a yaml dtab file, while it does provided it is json format.
3. when you update a dtab using a mismatched version (json), the error received client side is not that clear

Prerequisites

1. linkerd + namerd + namerctl
2. create some dtab named internal

Repro steps

1. download a dtab in yaml format: namerctl dtab get internal > internal.yaml
2. update the dtab using the yaml downloaded in step 1: namerctl dtab update internal internal.yaml
3. update the dtab twice: namerctl dtab update internal internal.yaml
   Note: please note that you should have been able update it successfully
4. download a dtab in json format: namerctl dtab get internal --json > internal.json
5. update the dtab using the json downloaded in step 4: namerctl dtab update internal internal.json
6. update the dtab twice: namerctl dtab update internal internal.json

Expected

It could either work like in step 3 for yaml format or at least both could behave in the very same way

Actual

Error: unexpected response: 412 Precondition Failed

Workaround

1. download the json file again so you get the updated version value.
2. as @rmars mentioned, you could just remove the version value from your json and it should behave similarly to yaml case.

Warning

I couldn't realize when/why. But at some point you might need to restart namerd to get the latest version. It looks like it get cached or similar.

Is there way how to set/update new dtab via tls?

the viper library, a sibling of cobra, supports loading configuration from a file. this would be extremely useful for loading base-url. We should support at least configuration in $PWD and $HOME. We may also want to support searching in all parent directories until we find a .namerdctl file, but we don't have to do that initially.